Institute of Resource and Environment, Henan Polytechnic University,
Jiaozuo 454003, Henan, China
Submission date: 2017-01-15
Final revision date: 2017-04-19
Acceptance date: 2017-04-22
Online publication date: 2017-09-18
Publication date: 2017-11-07
Pol. J. Environ. Stud. 2017;26(6):2785–2791